So you, like me, had a custom theme loaded into Windows XP with SP2, for which you needed to patch your uxtheme.dll to accept themes not signed by Microsoft. Therefore, again like me, you probably used the Neowin uxtheme.dll multipatcher, which works admirably well on SP2 and properly overrides Windows file protection. Fair enough.

However, you might have recently installed Windows XP Service Pack 3 (SP3), hoping for a faster, more secure system. If you're reading this, I assume that you were disappointed/ upset/ devastated to discover that XP SP3 replaces uxtheme.dll with a new, unpatched version, and trust me that trying to use the Neowin Multipatcher on SP3 makes the Themes service fail entirely. The solution is not terribly challenging, and I'll outline it in a few steps here. This is not totally original, but I figured it out through the synthesis of information on a few other sites.

1. The first step is to get a new uxtheme.dll, and SP3 version pre-patched to work properly with unofficial themes. Therefore, head to Uxtheme Patches at Within Windows and download the appropriate file. Use your favorite compressed file manager to extract uxtheme.dll to the desktop.

2. Next you'll need Replacer, a program intended to safely replace DLLs and work around Windows' built in system to prevent the replacement of DLLs. Head to the Replacer website and grab the stable version. Extract all the files in here to your desktop too.

3. Finally, double-click to launch the replacer.cmd file on your desktop, and follow the instructions. First, you'll need to open C:\Windows\System32, scroll down until you find uxtheme.dll, and drag this into the command window that Replacer should have opened. "C:\Windows\System32\uxtheme.dll" should now be in the window, so hit enter. Next minimize everything so you can see your desktop, and drag the new uxtheme.dll that you downloaded in. Again you should see the proper path in quotes, so hit enter again. You will be prompted if you're sure; if everything looks right, type Y and hit enter.

Voila! Restart and you should be all set. A caveat: it's possible, as with all modifications of Windows' core DLLs, that something may inexplicably go horribly wrong. I disclaim all responsibility in the unfortunate case this happens; you assume all risk by following these instructions. With that said, it worked fine for me, and as long as you download the correct version from Within Windows, you should be safe. Enjoy!

Awesome! This worked for me without hitches, although I no longer really need the patching anymore, as I am using an unofficial theme that was signed by Microsoft...

I used to use Vista Inspirat 2 before upgrading to SP3, but since the theme broke, I had to reset the theme back to the default. However, I didn't stick with it for long: I soon found an unofficial theme called Royale Noir that was special because it was signed by Microsoft, even if it was never officially released. For those people with XP who do not wish to change their theme too much, yet still want a more darker UI, you can get this theme directly here.

Glad to help. I've tried Royale Noir before, but I never liked the buttons on it; I prefer more Vista-esque toolbar buttons. My current theme, which I've been using for about a year now, is called VistaXP and is rather hard to find; here, this seems legit: http://vistaxp-v2-vs.en.softonic.com/.

Well, the reason I have been avoiding themes nowadays that look like Vista is because of the Start menu; I feel like if everything else looks like Vista, then so should the Start menu (even if I don't use it too much, favoring RocketDock even if I have the icon of the same program on the Desktop). Then I only have one choice: ViStart. And from previous experiences with ViStart, I can firmly say that there is a reason why it is still in Beta: numerous bugs (including one that makes it occasionally quit after running a program in fullscreen, which is annoying for me since I use my computer a lot for gaming), lots of performance issues, some incompatibilities, some missing items and the fact that its "Automatically start on Windows bootup" is just plain broken (for me, at least). The only two things I liked about it were the scrollable menu items in "All Programs" and that all the items were organized alphabetically (the latter being something I have missed a lot and have still yet to replicate it using the original XP start menu).

I also have had strongly negative experiences with ViStart, and I refuse to use it anymore; unfortunately, I think development has ceased on it. I'm happy enough with a dark theme, SegoeUI fonts, and oblong buttons without a Vista start menu, and I even have my icons spiffed up a bit with IconTweaker.

also, any flyakite users, uninstall the System Files Updater.

*I* planned ahead and googled before installing the upgrade.

Whew, I should hope you uninstall the System File Updater! It would run rampant over SP3.

Launchy ftw.

Also, this topic made me finally find patched theme files for Vista SP1, so I can use my older themes which were rendered unusable by SP1.

Launchy ftw indeed. I think you're the one who got me interested in it in the first place about a year ago; needless to say, I find it indispensible.